1. Field of the Invention
The present invention relates to a light source unit that mixes and emits excitation light from a light source and fluorescence generated by irradiating a fluorescent substance with excitation light; and a microscope including a light source unit that mixes and emits excitation light and fluorescence.
2. Description of the Related Art
In recent years, in accordance with improvements in luminous efficiency and luminance, microscopes provided with a transmitted illumination light-source unit that includes a white LED (light emitting diode) as a light source have often been seen. Some white LEDs use a system that uses LED chips of three colors, red, green and blue, and other white LEDs use a system that uses LED chips and fluorescent substances (hereinafter referred to as a “fluorescent substance system”), and, for example, Japanese Laid-open Patent Publication No. 2010-102095 discloses a microscope provided with a transmitted illumination light-source unit that uses as a light source a white LED adapted to the fluorescent substance system.
When a white LED adapted to the fluorescent substance system is used as a light source of a transmitted illumination light-source unit, light from the epi-illumination light-source unit that has passed through a sample may excite a fluorescent substance of the white LED while the sample is being observed via epi-illumination, thereby generating unnecessary fluorescence from the white LED.
A phenomenon such as this tends to occur particularly in a microscope provided with an epi-illumination light-source unit adapted to fluorescence observation, and, in fluorescence observation, fluorescence, which is typically an object to be detected, is weak, so the phenomenon greatly affects the observation result.
Technologies related to such a technical problem are disclosed by Japanese Laid-open Patent Publication No. 2010-102095 and Japanese Utility Model Application Publication No. 2-140514.
Japanese Laid-open Patent Publication No. 2010-102095 discloses a microscope system that includes: selecting means for selecting a transmitted illumination optical system or an epi-illumination optical system as an optical system for performing observation; and control means for, when the selected optical system is the epi-illumination optical system, controlling and causing light-shielding means to shield irradiation with epi-illumination light directed to a solid light-emitting element which is the light source of the transmitted illumination and to which a fluorescent substance is imparted.
Japanese Utility Model Application Publication No. 2-140514 discloses an epifluorescence microscope wherein an operator operates a dial so as to cause a shutter, light-shielding means, to be inserted into and withdrawn from a light path between a subject and a lens of a transmitted illumination system.
In the microscope system disclosed by Japanese Laid-open Patent Publication No. 2010-102095, when the epi-illumination optical system is selected, the control means controls turning-off of a solid light-emitting element, driving of the light-shielding means, and turning-on of an epi-illumination light source, and, as a result, the light-shielding means shields irradiation with epi-illumination light directed to the solid light-emitting element. Accordingly, users do not need to be conscious of operations of the light-shielding means and may cause the light-shielding means to act on irradiating of the solid light-emitting element with epi-illumination light without fail.
In the microscope system disclosed by Japanese Laid-open Patent Publication No. 2010-102095, the control means controls the light-shielding means by executing a control program using as an input a selection made by selecting means such as a mouse or a keyboard.
By contrast, in the epifluorescence microscope disclosed by Japanese Utility Model Application Publication No. 2-140514, a shutter is inserted in or withdrawn from a light source by operating a dial.